Cooling systems having an integrated ionic liquid salt dehumidification system

ABSTRACT

A cooling systems utilizes an organic ionic salt composition for dehumidification of an airflow. The organic ionic salt composition absorbs moisture from an inlet airflow to produce an outlet airflow with a reduce moisture from that of the inlet airflow. The organic ionic salt composition may be regenerated, wherein the absorbed moisture is expelled by heating with a heating device. The heating device may be an electrochemical heating device, such as a fuel cell, an electrochemical metal hydride heating device, an electrochemical heat pump or compressor, or a condenser of a refrigerant cycle, which may utilize an electrochemical pump or compressor. The efficiency of the cooling system may be increased by utilization of the waste heat the cooling system. The organic ionic salt composition may circulate back and forth or in a loop between a conditioner, where it absorbs moisture, to a regenerator, where moisture is desorbed by heating.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application claims the benefit of U.S. provisional patentapplication No. 62/413,986, entitled Cooling System Having An IntegratedIonic Liquid Salt Dehumidification System and filed on Oct. 28, 2016.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under Grant no.DE-EE0007040 awarded by Department of Energy. The government has certainrights in the invention.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a cooling system that incorporates anintegrated organic liquid salt dehumidification system

Background

Desiccant systems are widely used to absorb moisture in environments andcan be used to reduce the latent cooling load on HVAC systems; however,current technology use large amounts of heat to regenerate thedesiccant. Conventional air conditioning systems use vapor compressionrefrigeration (VCR) cycles to remove moisture from humid air throughcondensation. This requires inefficient cooling and reheating of theair. One of the keys to creating higher efficiency cooling systems is todehumidify air without over-cooling. Conventional HVAC systems achievecooling and dehumidification by cooling the air below its dew point tocondense the moisture and then reheat the air to provide it at thedesired conditions. Historically, ordinary (hydroscopic) salts, such asNaCl, LiCl, LiBr etc., have been used in HVAC applications as analternative means of dehumidifying the environment. This system has beentermed an ‘ILD’ for ionic liquid dehumidification system operating inconjunction with a heat pump, wherein, the heat from the heat pumpsystem is used to re-generate the ionic liquid. Separate sensible andlatent cooling dehumidify air as close, adiabatic if possible, and thensensibly cool it at higher evaporating temperature.

SUMMARY OF THE INVENTION

The invention is directed to a cooling system that incorporates anintegrated ionic liquid salt dehumidification system. An exemplary ionicliquid desiccant, or organic liquid salt, is a salt that comprisesorganic cations and inorganic or organic anions. These organic liquidssalts are thermally stable, have low vapor pressure, are not corrosiveto metals and have low driving temperatures to achieve dew pointtemperatures. A class of ionic salts have been identified that provideefficient moisture uptake and release that make them well suited forincorporation into a cooling system or a heating ventilation andcooling, HVAC system.

Ionic liquid desiccants, or organic liquid salts, are evaluated anddescribed in publication hereinafter Qu: Ming Qu, et al, AqueousSolution of [EMIM][OAc]: Property Formulations for use in airconditioning equipment design, Journal, Applied Thermal Engineering 124(2017) pages 271-278, 2017; the entirety of which is hereby incorporatedby reference herein. The organic liquid salts evaluated in this paperare identified in FIGS. 1 and 2. After extensive investigations of thesethirteen different ionic liquid desiccants, 1-Ethyl-3-methylimidazoliumacetate [EMIM][OAc], FIG. 2, was identified to exhibit the highestcapacity to absorb and desorb water vapor under realistic operatingregimes and can be regenerated by using low grade heat. As provided inthis paper, 1-Ethyl-3-methylimidazolium acetate has a molecular mass of170.21. In addition, some relevant properties and performancecharacteristics from this paper are provided Table 1 to 4.

TABLE 1 Summary of moisture adsorption of ionic liquids. Ionic liquidsEMIm HMIm MPPy HMpy BMIm EMIm HMIm TFSI TFSI TFSI TFSI Tf BF4 BF4Initial water content 43 46 54 46 116 318 252 (ppm) Maximum Adsorption99.24 99.48 99.52 99.77 94.89 91.15 93.69 (wt. %) Minimum adsorption99.92 99.91 99.97 99.98 99.94 98.78 99.20 (wt. %) Working Range (wt. %)0.68 0.43 0.45 0.21 5.05 7.63 5.51 Moisture adsorption = IL/(IL + H₂O) *100.

TABLE 2 Ionic liquids EMIm HMIm EMIm BMIm EMIm BMIm OAc OAc ES Ms DEPDBP Initial water 1265 249 266 435 515 443 content (ppm) Maximum 67.6684.86 78.64 76.21 75.28 86.25 Adsorption (wt. %) Minimum 91.09 96.6795.53 93.93 92.32 97.35 adsorption (wt. %) Working Range 23.43 11.8116.89 17.72 17.04 11.1 (wt. %)

TABLE 3 1-Ethyl-3-methylimidazolium acetate, C₈H₁₄N₂O₂ ρ (g/cm³) T (K)η_(D) (cp) T (K) K (S/m) T (K) 1.03 [12] 298.15 162 [11] 293.15 0.28[11] 293.15  91 [12] 298.15

TABLE 4 T_(m) (K) 228.15 [24, 42] 259.15 [7] 253.15 [12]

FIGS. 3 to 18 provide specific detail regarding a preferred ionic salt,EMIM Oac, 1-Ethyl-3-methylimidazolium acetate, as well as details ofthis salt in a binary mixture with water. The ionic salts or ionic saltmixtures may be used to absorb moisture from an inlet air flow that iscooled by a condenser or other cooling device and the ionic salt of saltmixtures may be regenerated by a heating device. A vapor compressioncycle, or refrigerant cycle, comprises a condenser, wherein a vapor iscondensed wherein a latent heat of vaporization may be used toregenerate the ionic salt composition. The condenser may be in thermalcommunication with the ionic salt composition, as described herein, toregenerate the salt so that it may absorb more moisture. The salt or abinary salt mixture composition may be circulated to absorb moisturefrom the air or vapor to be cooled and then passed by a heating device,such as a condenser, fuel cell, electrochemical pump, metal hydrideheating device, for example to desorb the moisture from the ionic salt,or binary salt mixture.

An exemplary cooling system comprises a dehumidification systemcomprising an organic ionic salt composition that absorbs moisture froman inlet airflow. The cooling system comprises a cooling device such asan evaporator and a heating device that regenerators the organic ionicsalt composition by heating it to drive out moisture. The organic ionicsalt composition may be configured to flow back and forth or in a loopbetween a conditioner to a regenerator. In the conditioner, the organicionic salt composition absorbs moisture and in the regenerator, moistureis expelled or reduced from the organic ionic salt composition. Theconditioner may be coupled with an airflow through a cooling system. Theoutlet airflow from the cooling system is cooler and has a lowerhumidity or moisture content than the inlet airflow to the coolingsystem, as the moisture is removed by the ionic liquid dehumidificationsystem.

The cooling system may be a traditional refrigeration system having acompressor, a condenser, an evaporator, and an expansion valve. Thecooling device may be the evaporator and the heating device used in theregenerator may be the condenser. The refrigerant cycle may incorporatea traditional compressor or preferably an electrochemical compressor, asit is more efficient. The heat from the electrochemical compressorand/or the condenser may be used in a regenerator to expel moisture fromthe ionic liquid desiccant, such as organic liquid salt composition.

In another embodiment, the heating device of the regenerator is a fuelcell, such as polymer electrolyte membrane fuel cell. The waste heatfrom the fuel cell may be in thermal communication with the organicliquid salt composition to drive out moisture and the energy producedfrom the fuel cell may be used in the cooling system, such as to drivepumps, operate switches and the like.

In another embodiment, the heating device is a metal hydride heatingdevice. A metal hydride may be contained in an enclosure and whenhydrogen is absorbed it may generate heat that can be used to regeneratethe organic liquid salt composition. In one embodiment, a metal hydridesystem comprise two enclosures for metal hydride and hydrogen is pumpedback and forth or in a loop between them, wherein one enclosuregenerates heat and one absorbs heat. Therefore, the organic liquid saltcomposition may be exposed to the heating enclosure and the endothermicenclosure may be used to cool an airflow, or used as a cooling device asused herein. Valves may be used to control the flow of the organicliquid salt composition to the appropriate metal hydride enclosure.Likewise, valves may be used to control the flow of airflow over theappropriate metal hydride enclosure to cool the airflow.

An exemplary organic liquid salt composition comprises an organic ionicsalt that is mixed with a liquid, such as water. Exemplary organic ionicsalts are detailed, but not limited to those shown in FIGS. 1 and 2.Organic ionic salts may be mixed with water to produce a binary mixturethat can be pumped from a conditioner to a regenerator.

An exemplary cooling system comprises a dehumidification loop, whereinthe organic liquid salt composition flows from a conditioner, wherein itis exposed to the inlet air to absorb humidity from the inlet air, to aregenerator, wherein the organic liquid salt composition is in thermalcommunication with the heating device to desorb the absorbed moisture ofthe organic ionic salt.

The cooling system, as describe herein, may comprise or incorporate anyof the components describe in the references incorporated by referenceherein. This application incorporates by reference the entirety of U.S.application Ser. No. 15/289,220, filed on Oct. 10, 2016 and entitledElectrochemical Heat Transfer System, U.S. application Ser. No.13/029,006 filed on Feb. 16, 2011 entitled Electrochemical Heat TransferSystem, U.S. Pat. No. 8,627,671 issued on Jan. 14, 2014 and entitledSelf-Contained Electrochemical Heat Transfer System, U.S. ApplicationNo. 61/215,131 filed on May 1, 2009, and U.S. application Ser. No.13/029,006, U.S. Application No. 61/305,410, filed on Feb. 17, 2010 andentitled Electrochemical Heat Pump System for Cooling ElectronicComponents, and to U.S. Application No. 61/347,428, filed May 23, 2010and entitled Compact Cooling Systems Using Electrochemical Compression.

This application incorporates by reference the entirety of U.S.provisional patent application No. 62/277,399, to Xergy Inc., filed onJan. 11, 2016 and entitled Hydrogen Sorption and Desorption Heat PumpSystem, U.S. provisional patent application No. 62/288,417 to XergyInc., filed on Jan. 28, 2016 and entitled Electrochemical CompressorDriven Metal Hydride Heating Element For Heating and CoolingApplications, U.S. provisional patent application No. 62/292,529, toXergy Inc., filed on Feb. 8, 2016, and entitled Advanced Metal HydrideHeat Pump Using Electrochemical Hydrogen Compressor, U.S. provisionalpatent application No. 62/297,123, to Xergy Inc., filed on Feb. 18, 2016and entitled Hydrogen Sorption and Desorption Heat Pump System, U.S.provisional patent application No. 62/300,082, to Xergy Inc., filed onFeb. 26, 2016 and entitled Advanced Metal Hydride Heat Pump UsingElectrochemical Hydrogen Compressor, U.S. provisional patent applicationNo. 62/303,300, to Xergy Inc., filed on Mar. 3, 2016 and entitled Plateand Frame Metal Hydride Heat Exchanger, U.S. provisional patentapplication No. 62/308,060, to Xergy Inc., filed on Mar. 14, 2016 andentitled Advanced Hydride Hot Water Heater, U.S. provisional patentapplication No. 62/315,664, to Xergy Inc., filed on Mar. 30, 2016 andentitled Water Management Apparatus For Metal Hydride Heat ExchangersWith Electrochemical Compressor, U.S. provisional patent application No.62/324,337, to Xergy Inc., filed on Apr. 18, 2016 and entitled HighEfficiency Heat Pump, and U.S. provisional patent application No.62/326,532, to Xergy Inc., filed on Apr. 22, 2016 and entitled NickelMetal Hydride Heat pump.

This application incorporates by reference the entirety of U.S.provisional patent application No. 62/244,709, filed on Oct. 21, 2015and entitled System and Method of Water Purification Utilizing anIonomer Membrane, U.S. provisional patent application No. 62/385,178,filed on Sep. 8, 2016 and entitled Electrochemical Desalination Systemand U.S. provisional patent application No. 62/385,176, filed on Sep. 8,2016 and entitled Ozone Generator System.

This application incorporates by reference the entirety of U.S. patentapplication Ser. No. 15/475,124, filed on Mar. 30, 2017, entitled HeatPumps Utilizing Ionic Liquid Desiccant and currently pending.

An exemplary cooling system of the present inventions comprises an ionicliquid dehumidification system comprising an ionic liquid desiccantcomposition comprising an ionic liquid desiccant and water. The ionicliquid desiccant is pumped from a conditioner, where it absorbs moisturefrom a conditioner fluid, to a regenerator, where moisture is desorbedor driven out from the ionic liquid desiccant, such as into aregenerator fluid. An exemplary ionic liquid desiccant dehumidificationsystem comprises exchangers, or exchange modules for the transfer to andfrom the ionic liquid desiccant. An exchange module comprises animpermeable exchange membrane having no bulk flow of air therethrough.An exemplary impermeable exchange membrane has a Gurley Densometer valueof more than about 500 seconds and preferably more than 1000 seconds,thereby having no bulk flow of air through the thickness. This test canbe performed on a Gurley Densometer, such as an automatic GurleyDensometer, model 4340 from Gurley Instruments, Inc. Water may absorbinto the impermeable exchange membrane and pass therethrough, howeverair and gas will not flow through the membrane. An exemplary impermeableexchange membrane has little porosity, such as no more than about 10%porosity and preferably no more than about 5% or 2%. An exemplaryimpermeable exchange membrane comprises a continuous film of polymerthat can seal air from one side to the opposing side. The exchangemembrane may comprise a cation exchange or conductive polymer, such asionomer, such as perfluorosulfonic acid polymer, ie. Nafion. Theexchange membrane may comprise an anion exchange or anion conductivepolymer, as detailed in applications incorporated by reference herein.The exchange membrane may a high moisture transport polymers such asurethane, or silicone, for example. An exemplary impermeable exchangemembrane is very thin to promote high rates of moisture transporttherethrough and is no more than 30 microns and preferably no more than25 microns, or no more than 20 microns, such as 15 microns or less. Toprovide additional support for these thin impermeable exchangemembranes, a support layer may be coupled with the exchange polymer,such as the ionomer. A support layer may be embedded partially orcompletely within the exchange polymer or ionomer. A support layer maybe exposed on one or both sides of the exchange membrane. An exemplarysupport layer is a porous non-woven material, such as a fluoropolymermembrane, available from W.L. Gore and Associates, or Cellguard,available from 3M.

In an exemplary exchange module, conditioner fluid, such as air that iscooled and dehumidified flows past one side of an exemplary impermeableexchange membrane and ionic liquid desiccant flows past the opposingside. Water from the conditioner air passes through the impermeableexchange membrane and into the ionic liquid desiccant. The ionic liquiddesiccant is then transferred to the regenerator module wherein aregenerator fluid flows past one side to absorb moisture from the ionicliquid desiccant. The ionic liquid desiccant may be heated in aregenerator, such as prior to entering the exchange module or exchangeror within the exchanger. A heating device may be thermally coupled withthe regenerator to heat the ionic liquid desiccant. The heating devicemay be a resistive heater, or may be a device used in a refrigerationsystem or in the ionic liquid desiccant dehumidification system, such aswaste heat from a pump, a controller, a compressor, and the like. Aheating device may be a compressor of a refrigeration system and thiscompressor may be an electrochemical compressor. A heating device maybea metal hydride heating element. A heating device may be a pump forpumping the ionic liquid desiccant or a working fluid or refrigerantthrough a refrigerant system.

The summary of the invention is provided as a general introduction tosome of the embodiments of the invention, and is not intended to belimiting. Additional example embodiments including variations andalternative configurations of the invention are provided herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the description serve to explain the principles of theinvention.

FIGS. 1 and 2 show the chemical diagram of some preferred organic ionicsalt as described in the present invention.

FIGS. 3 and 4 show graphs of vapor pressure verus mass fraction of waterand EMIM Oac, 1-Ethyl-3-methylimidazolium acetate respectively.

FIG. 5, from Qu, shows a graph of specific heat capacity versustemperature for mixtures of 1-Ethyl-3-methylimidazolium Acetate andWater.

FIG. 6, from Qu, shows the density of binary mixtures of EMIM.OAc, as afunction of the mass fraction of EMIM.OAc.

FIG. 7 shows the dynamic viscosities of aqueous solution of EMIM.OAcversus various temperatures and mass fractions of EMIM.OAc.

FIG. 8 shows an exemplary ionic liquid dehumidification system.

FIG. 9 shows a diagram of an exemplary conditioner.

FIG. 10 shows a diagram of an exemplary regenerator.

FIGS. 11 and 12 show exemplary tube-in-tube exchangers.

FIG. 13 shows a diagram of an exemplary refrigerant system comprising anexemplary ionic liquid desiccant dehumidification system.

FIG. 14 shows an exemplary fuel cell.

FIG. 15 shows an exemplary hydrogen pump.

FIG. 16 shows an exemplary metal hydride heating system.

FIG. 17 to 19 show cross-sections of exemplary impermeable exchangemembrane.

FIGS. 20 and 21 show test results of humidity versus time for anexemplary test ionic liquid dehumidification system.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Corresponding reference characters indicate corresponding partsthroughout the several views of the figures. The figures represent anillustration of some of the embodiments of the present invention and arenot to be construed as limiting the scope of the invention in anymanner. Further, the figures are not necessarily to scale, some featuresmay be exaggerated to show details of particular components. Therefore,specific structural and functional details disclosed herein are not tobe interpreted as limiting, but merely as a representative basis forteaching one skilled in the art to variously employ the presentinvention.

As used herein, the terms “comprises,” “comprising,” “includes,”“including,” “has,” “having” or any other variation thereof, areintended to cover a non-exclusive inclusion. For example, a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to only those elements but may include otherelements not expressly listed or inherent to such process, method,article, or apparatus. Also, use of “a” or “an” are employed to describeelements and components described herein. This is done merely forconvenience and to give a general sense of the scope of the invention.This description should be read to include one or at least one and thesingular also includes the plural unless it is obvious that it is meantotherwise.

In cases where the present specification and a document incorporated byreference include conflicting and/or inconsistent disclosure, thepresent specification shall control.

Certain exemplary embodiments of the present invention are describedherein and are illustrated in the accompanying figures. The embodimentsdescribed are only for purposes of illustrating the present inventionand should not be interpreted as limiting the scope of the invention.Other embodiments of the invention, and certain modifications,combinations and improvements of the described embodiments, will occurto those skilled in the art and all such alternate embodiments,combinations, modifications and improvements are within the scope of thepresent invention.

FIGS. 1 and 2 show the chemical diagram of some preferred organic ionicsalt as described in the present invention.

FIGS. 3 and 4 show graphs of vapor pressure verus mass fraction of waterand EMIM Oac, 1-Ethyl-3-methylimidazolium acetate respectively. Thesefigures are from the following paper: 1. Christiane Römich, et al,Thermodynamic Properties of Binary Mixtures of Water andRoom-Temperature Ionic Liquids: Vapor Pressures, Heat Capacities,Densities, and Viscosities of Water+1-Ethyl-3-methylimidazolium Acetateand Water+Diethylmethylammonium Methane Sulfonate J. Chem. Eng. Data,2012, 57 (8), pp 2258-2264, the entirety of which is hereby incorporatedby reference.

FIG. 5, from Qu, shows a graph of specific heat capacity versustemperature for mixtures of 1-Ethyl-3-methylimidazolium Acetate andWater. The mole fraction of the 1-Ethyl-3-methylimidazolium Acetate isprovided on the graph, wherein 0 is 100% water. The equation for thespecific heat as a function of the mixture is provided below in Equation1:

$\begin{matrix}{C_{{{{p\_}{\lbrack{EMIM}\rbrack}}{\lbrack{OAc}\rbrack}}_{H\; 2\; O}} = {2.761077 + {0.008120T} - {1.10615*10^{- 5}T^{2}} - {2.649514\mspace{11mu}\xi} - {0.918307\mspace{11mu}\xi^{2}} + {0.003580T\;\xi}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

Where, T is the binary temperature in K, and

is the mass fraction of EMIM.OAc.

FIG. 6, from Qu, shows the density of binary mixtures of EMIM.OAc, as afunction of the mass fraction of EMIM.OAc. The equation for density as afunction of temperature. T in Kelvin and mass fraction of EMIM.OAc isprovide in equation 2.

$\begin{matrix}{\rho_{{\lbrack{EMIM}\rbrack},{\lbrack{OAc}\rbrack}_{H_{2}O}} = {{1.012482*10^{3}} - {0.918103T} + {6.25*10^{- 5}T^{2}} + {758.0905\mspace{11mu}\xi} - {497.846\mspace{11mu}\xi^{2}} + {0.302582T\;\xi}}} & {{Equation}\mspace{14mu} 2}\end{matrix}$

FIG. 7 shows the dynamic viscosities of aqueous solution of EMIM.OAcversus various temperatures and mass fractions of EMIM.OAc. The equationfor dynamic viscosity is provided in Equation 3 where T is temperaturein Kelvin and

is the mass fraction of EMIM.OAc.Ln(η_([EMIM][OAc]) _(_) _(H) ₂ _(O))=3.025114−0.150834T+2.20875*10⁻⁴ T²−0.40864ξ−9.363176ξ²+0.030720Tξ  Equation 3:

FIG. 8 shows an exemplary ionic liquid dehumidification system 10comprising a conditioner 40 that removes moisture from a fluid, such asair, and a regenerator 60 that comprises a heating device 69 to removethe moisture in the ionic liquid desiccant 12. The ionic liquiddesiccant flows in a loop from the conditioner to the regeneratorthrough a post conditioner conduit 41 and from the regenerator to theconditioner through a post regenerator conduit 61. The conditionercomprises an exchanger 43 wherein the ionic liquid desiccant flows pastan impermeable exchange membrane 50 on a first side, and the conditionerfluid 14, such as air, flows past the impermeable exchange membrane on asecond and opposing side. Likewise, the conditioner comprises anexchanger 63 wherein the ionic liquid desiccant flows past animpermeable exchange membrane 50′ on a first side, and the conditionerfluid 16, such as air, flows past the impermeable exchange membrane on asecond and opposing side. An exemplary impermeable exchange membrane isan ionomer membrane comprising a proton conducting ionomer. Theconditioner fluid 14 enters the conditioner through a fluid inlet 46 atan inlet humidity level and temperature and exits the conditionerthrough a fluid outlet 48 at an outlet humidity level and temperature.The conditioner fluid outlet humidity level of will be less than theconditioner fluid inlet humidity level as moisture from the conditionerfluid is absorbed into the ionic liquid desiccant through theimpermeable exchange membrane 50 in the exchanger 43. The regeneratorfluid 16 enters the regenerator through a fluid inlet 66 at an inlethumidity level and temperature and exits the regenerator through a fluidoutlet 68 at an outlet humidity level and temperature. The regeneratorfluid outlet humidity level will be higher than the regenerator fluidinlet humidity level as it absorbs moisture from the ionic liquiddesiccant through the impermeable exchange membrane in the exchanger 63.An exchanger may comprise a plate and frame type exchanger that providesone or more channels for the flow of the ionic liquid desiccant and theconditioner fluid or regenerator fluid. A conditioner exchanger 43 maybe a counter flow exchanger, as shown, wherein the ionic liquiddesiccant inlet 42 and outlet 44 are opposite the inlet and outlet ofthe conditioner fluid 14. A regenerator exchanger 63 may be a counterflow exchanger, as shown, wherein the ionic liquid desiccant inlet 62and outlet 64 are opposite the inlet and outlet of the conditioner fluid16. An exchanger may be a tube-in-tube exchanger, wherein one of theconditioner or regenerator fluid flows around the tube and the ionicliquid desiccant flow within the tube. The tube may comprise, consistessentially of or consist of an impermeable exchange membrane. Anexemplary conditioner may be part of a cooling system 20 for an aircooling system for a dwelling, for example. The exemplary ionic liquiddehumidification system comprises a controller 70 for controlling thefunctions of the system, such as controlling a pump 72 and/or a valve 73for the ionic liquid desiccant flow. A controller may interface withsensors, such a humidity sensors 78-78′″ and/or temperature sensors74-74′″ to determine a flow rate of the ionic liquid desiccant. A flowsensor 79 may provide input to the controller of the flow rate of theionic liquid desiccant. A temperature sensor 77 may be used to determinethe temperature of the ionic liquid desiccant and/or a temperatureproduced by the heating device 69. A controller may have amicroprocessor 76 that runs a computer program to control the functionsof the system.

As shown in FIG. 9, an exemplary conditioner 40 comprises a conditionerfluid conduit 47 for the flow of a conditioner fluid 14 on a conditionerside 54 of an impermeable exchange membrane 50 and an ionic liquiddesiccant conduit 45 for the flow of ionic liquid desiccant 12 on theionic liquid desiccant side 55 of the impermeable exchange membrane 50.Water 18 is transferred through the impermeable exchange membrane 50from the conditioner fluid 14 to the ionic liquid desiccant 12. Theexchanger is a counter flow exchanger wherein the inlet 46 and out 48 ofthe conditioner fluid 14 are opposite the inlet 42 and outlet 44 of theionic liquid desiccant 12.

As shown in FIG. 10, an exemplary regenerator 60 comprises a regeneratorfluid conduit 67 for the flow of a regenerator fluid 16 on a regeneratorside 64 of an impermeable exchange membrane 50 and an ionic liquiddesiccant conduit 65 for the flow of ionic liquid desiccant 12 on theionic liquid desiccant side 57 of the impermeable exchange membrane 50.Water 18 is transferred through the impermeable exchange membrane 50from the ionic liquid desiccant 12 to the regenerator fluid 16. Theexchanger is a counter flow exchanger wherein the inlet 66 and out 68 ofthe regenerator fluid 16 are opposite the inlet 62 and outlet 64 of theionic liquid desiccant 12.

As shown in FIGS. 11 and 12, an exchanger may be a tube-in-tubeexchanger. FIG. 11 shows an exemplary conditioner 40 comprising aconditioner exchanger 43 that is a tube-in-tube exchanger 53 having aconditioner fluid conduit 47 configure around an ionic liquid desiccantconduit 45. FIG. 12 show a regenerator exchanger 63 that is atube-in-tube exchanger 53 having a regenerator fluid conduit 67 aroundan ionic liquid desiccant conduit 65. The exemplary regenerator 60 has aheating device 69 within the ionic liquid desiccant conduit 65 andoptionally may have a heating device 69′ around the regenerator fluidconduit. The entire tube-in-tube exchanger may flow through a heatingdevice.

As shown in FIG. 13, an exemplary refrigeration 310 comprises acompressor 318 a condenser 316 and expansion valve 350 and an evaporator315. The evaporator cools the air before it enters into an enclosure190. A liquid ionic desiccant system 100 is configured to reduce themoisture content of the incoming air 301 into the desiccant chamber. Theoutlet air 302 from the desiccant chamber will have a lower moisturecontent than the incoming air. The air entering the enclosure 303 willbe cool and dry. The enclosure shown is a home. Note that the desiccantchamber may be configured before or after the evaporator or coolingdevice. The compressor has a low pressure side 352 and a high pressureside 354. The compressor may be a mechanical compressor or anelectrochemical compressor 312 comprising a membrane electrode assembly314. The refrigeration system has a plurality of sensors 348, acontroller 330 that may run a control program 356 on a microprocessor,for example. The conditioner 40 comprises a liquid ionic desiccant 110that absorbs moisture from the incoming air 301. The airflow through theconditioner 40 portion of the ionic liquid dehumidification systemreduces the moisture content of the air flow 303 entering the dwelling190 and the evaporator 315 further cools the air. The ionic liquiddehumidification system 10 has a regenerator 60 that may be configuredto absorb heat from the compressor 318 to drive moisture from the ionicliquid desiccant. The regenerator may be in thermal contact with thecompressor 318 and may be physically coupled to the compressor such asby a heat exchanger. Conduits 41 and 61 transfer the ionic liquiddesiccant between the conditioner and the regenerator. Conduits 326transport the working fluid through the refrigeration system.

FIG. 14 shows an exemplary fuel cell having an ion conducting layerseparating an anode from a cathode. The ion conducting layer maycomprise an ionomer and may be a composite ionomer membrane comprising asupport material, such as a fluoropolymer membrane. An exemplary fuelcell may be used in a refrigeration system and may be a heating devicefor the regenerator in an ionic liquid dehumidification system. Powerproduced by the fuel cell may be used to power portions of the ionicliquid dehumidification system. As shown in FIG. 14, an electrochemicalcompressor 421 comprises a fuel cell 414 having an anode 446, an ionconductive membrane 449 and a cathode 48. Water is introduced on theanode side 445 and is converted into protons, H⁺, that are transportedacross the ion conducting membrane 449 to the cathode side 447. A gasdiffusion media 470, 470′ is configured in direct and electrical contactwith the anode and cathode respectively. An exemplary fuel cell 414comprises an electrochemical cell 420. The fuel cell comprises amembrane electrode assembly 442 comprising a proton conducting membrane449, an anode 446 and cathode 448. A membrane electrode assembly may insome cases include a gas diffusion media 470, 470′. A flow field 472,472′, typically comprising an electrically conductive plate havingchannels for the delivery of gasses to the surface of the membraneelectrode assembly, is configured on either side of the membraneelectrode assembly. The anode side 445 of the fuel cell convertshydrogen to protons, H⁺, which are then transported across the membraneto the cathode side 447. At the cathode, the protons react with oxygento produce water and the water produced moves through the compressoroutlet 452 and into conduit 450. This transfer, or pumping, of protonsacross the membrane produces an increased pressure on the cathode side.The anode side 445 is the low pressure side 443, and the cathode side447 is the high pressure side 444 of the electrochemical compressor 420.The hydrogen inlet 440 and oxygen inlet 441 are shown. A fuel cellproduces heat and this heat may be used in a regenerator and may be aheating device in a ionic liquid dehumidification system as describedherein.

Referring now to FIGS. 15 and 16, FIG. 15 shows a diagram of anelectrochemical hydrogen pump 512, or electrochemical compressor, thatmay be used as an electrochemical compressor. A proton associable fluid590 may be pumped through the ion conducting layer 534 from an anodeside 535 to a cathode side 536, or from an inlet 520 to an outlet 522,on a high pressure side. The anode 530 and cathode 532 are coupled by apower source 528 that drives the reactions. The membrane electrodeassembly 513 may comprise an ionomer or ionomer membrane. Theelectrochemical compressor may be used in a refrigeration system and maybe a heating device for the regenerator in an ionic liquiddehumidification system.

As shown in FIG. 16, an exemplary metal hydride electrochemical heattransfer device 510 that comprises an electrochemical hydrogencompressor 512. The electrochemical compressor 512 pumps hydrogen froman anode side 535, and from a first metal hydride reservoir 540 acrossthe membrane electrode assembly 513 to the cathode side 536 and into asecond metal hydride reservoir 550 such as a tank or enclosure for themetal hydride forming alloy 553 material. The metal hydride 552 materialmay be a packed bed or a monolith for example. The metal hydridereservoir may comprise an additive such as fluoropolymer, silica ormetal such as copper, to aid in expansion and contraction of the metalhydride. The compressor may be reversed, wherein the controller changesthe potential of the power supply 528 to switch the anode to the cathodethe cathode to the anode. In this way, hydrogen can be pumped back andforth between the two metal hydride reservoirs. Heat transfer devices547, 557 are coupled to the metal hydride portion 540, 550 respectively.The heat transfer device may transfer heat to and/or from the metalhydride reservoir to an article or to the air or environment. A heattransfer device may comprise fins, a conduit for a flow of a heattransfer fluid, a conducting plate, and the like. A heat transfer devicemay be thermally coupled with a regenerator of an ionic liquid desiccantdehumidification system, as described herein.

As shown in FIGS. 17 through 19, an ionomer layer 634 is a compositeionomer membrane 669 having a reinforcing material 662. The reinforcingmaterial 662, such as a membrane or discrete reinforcing elements orfibers, may be configured within the ionomer 660, wherein the ionomer isexposed on either side of the reinforcing material, as shown in FIG. 17.In an alternative embodiment, the reinforcing material is configured toone side of the composite ionomer membrane 669, as shown in FIG. 18. Inanother embodiment, the reinforcing material 662 extends through thethickness 665 of the composite ionomer membrane 669, wherein there issubstantially no ionomer layer on the top or bottom surface, as shown inFIG. 19. The composite ionomer membrane may be very thin to enable quicktransfer of hydrogen and therefor a higher heating flux rate. Thecomposite ionomer membrane may be about 30 μm or less, about 25 μm orless, about 20 μm or less, about 15 μm or less, about 10 μm or less,about 5 μm or less. The ionomer 60 interpenetrates the reinforcingmaterial 62. The ionomer and/or the composite ionomer may have anadditive 668, to improve performance such as silica or other desiccantparticles, or reinforcing materials, as described herein.

As shown in FIGS. 20 and 21, a test apparatus was constructed to measurethe rate of moisture transfer through an impermeable exchange membrane,Nafion 211, or a perfluorosulfonic acid polymer that was approximately25 microns thick, and 1100 equivalent weight. The test chamber was 40.6cm cubed and one side had a 588 cm2 impermeable exchange membraneconfigured between the chamber and a flow of ionic liquid desiccant. Theionic liquid desiccant was IoLiTech Ionic Liquids Technologies. GmbH, aswas the 1-Ethyl-3-methylimidazolium acetate [EMIM][OAc]. The test ILDweight was 194.6 g, density 1.1 g/cc, and 95% concentration. For theabsorption portion of the test, wherein moisture was absorbed from thechamber into the ionic liquid desiccant through the membrane, the inletmass flow rate of the ionic liquid desiccant was 0.620 g/c and theoutlet mass flow rate was 0.337 g/s. The airflow rate through thechamber was 1.12×10-04 CFM. For the desorption test, the aiflow rate was1.12×10-04 CFM, the ILD inlet mass flowrate was 0.837 g/s and the outletmass flowrate was 0.415 g/s. FIG. 20 shows the rate of relative andabsolute humidity drop as the ionic liquid desiccant flowed past theexchange membrane to absorb moisture from the test chamber. FIG. 21 showa desorption of the moisture from the ionic liquid desiccant back intothe chamber, wherein the ionic liquid desiccant was heated in this phaseto promote the desorption of the moisture from the ionic liquiddesiccant. The benchtop prototype for desiccating an ionic liquiddesiccant (ILD) had a plurality of channels for exchanging moisture fromthe ILD with dry gas, such as air. The benchtop prototype produced aconfirmed savings of about 21% of the energy required for HVACapplications based on our small-scale prototype. At the heart of thisdemonstration unit was a ‘ionic membrane’ contactor in a plate and frametype arrangement that provided an active surface for moisture absorptionand desorption. In testing, we determined that the ionic salts arecorrosive in nature, requiring careful selection of materials ofconstruction. For highest performance, the desiccant system requiredlarge surface area relative to the ionic salt mass.

It will be apparent to those skilled in the art that variousmodifications, combinations and variations can be made in the presentinvention without departing from the spirit or scope of the invention.Specific embodiments, features and elements described herein may bemodified, and/or combined in any suitable manner. Thus, it is intendedthat the present invention cover the modifications, combinations andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A cooling system comprising an ionic liquiddehumidification system comprising: a) an ionic liquid desiccantcomposition comprising: i) an ionic liquid desiccant; ii) water; b) aconditioner comprising: i) a conditioner ionic liquid desiccant conduithaving: an ionic liquid desiccant inlet; an ionic liquid desiccantoutlet; wherein the ionic liquid desiccant composition flows through theconditioner ionic liquid desiccant conduit; ii) a conditioner fluidconduit having: a conditioner fluid inlet; a conditioner fluid outlet;wherein a conditioner fluid flows through the conditioner fluid conduit;and iii) an impermeable exchange membrane configured between theconditioner ionic liquid desiccant conduit and the conditioner fluidconduit; wherein the conditioner fluid comprises moisture that istransferred through the conditioner impermeable exchange membrane to theionic liquid desiccant flowing through the conditioner ionic liquiddesiccant conduit; c) a regenerator; i) a regenerator ionic liquiddesiccant conduit having: an ionic liquid desiccant inlet; an ionicliquid desiccant outlet; wherein the ionic liquid desiccant compositionflows through the regenerator ionic liquid desiccant conduit; ii) aregenerator fluid conduit having: a regenerator fluid inlet; aregenerator fluid outlet; wherein the regenerator fluid flows throughthe regenerator fluid conduit; i) an impermeable exchange membraneconfigured between the regenerator ionic liquid desiccant conduit andthe regenerator fluid conduit; d) a compressor that heats the ionicliquid desiccant so that ionic liquid desiccant is heated to atemperature greater than the temperature of ionic liquid desiccant inthe conditioner; wherein the ionic liquid desiccant flowing through theregenerator comprise moisture absorbed from the conditioner that istransferred through the regenerator impermeable exchange membrane to theregenerator fluid flowing through the regenerator fluid conduit; e) apump that pumps the ionic liquid desiccant composition in a loop fromthe conditioner to the regenerator; wherein the ionic liquid desiccantcomposition has a lower moisture content at the conditioner fluid outletthan at the conditioner fluid inlet and wherein the ionic liquiddesiccant composition has a lower temperature at the conditioner fluidoutlet than at the conditioner fluid inlet.
 2. The cooling system claim1, wherein the ionic liquid desiccant is an organic ionic salt.
 3. Thecooling system of claim 2, wherein the organic ionic salt is1-Ethyl-3-methylimidazolium acetate [EMIM][OAc].
 4. The cooling systemof claim 2, wherein the organic ionic salt composition is configured ina binary mixture with water.
 5. The cooling system of claim 1, hereinthe cooling system further comprises: a) a condenser; and b) anevaporator.
 6. The cooling system of claim 5, wherein the compressor isan electrochemical compressor.
 7. The cooling system of claim 6, whereinthe electrochemical compressor is a polymer electrolyte membranecompressor and wherein the polymer electrolyte membrane comprises anionomer.
 8. The cooling system of claim 7, wherein the ionomer comprisesperfluorosulfonic acid.
 9. The cooling system of claim 1, furthercomprising a fuel cell to provide electrical power to the coolingsystem.
 10. The cooling system of claim 9, wherein the fuel cell heatsthe ionic liquid desiccant in the regenerator.
 11. The cooling system ofclaim 10, wherein the fuel cell is a polymer electrolyte fuel cellcomprising an ionomer membrane.
 12. The cooling system of claim 1,further comprising a metal hydride electrochemical heat transfer devicethat heats the ionic liquid desiccant in the regenerator wherein themetal hydride electrochemical heat transfer device comprising anelectrochemical pump for pumping hydrogen to an enclosure comprisingmetal hydride.
 13. The cooling system of claim 1, wherein theimpermeable exchange membrane comprises an ionomer.
 14. The coolingsystem of claim 13, wherein the impermeable exchange membrane has aGurley value of more than 500 seconds.
 15. The cooling system of claim1, wherein the impermeable exchange membrane has a thickness of no morethan about 25 microns.
 16. The cooling system of claim 15, wherein theimpermeable exchange membrane comprises a support layer.
 17. The coolingsystem of claim 16, wherein the support layer a fluoropolymer membranesupport layer.
 18. A cooling system comprising an ionic liquiddehumidification system comprising: a) an ionic liquid desiccantcomposition comprising: i) an ionic liquid desiccant: ii) water; b) aconditioner comprising: i) a conditioner ionic liquid desiccant conduithaving: an ionic liquid desiccant inlet; an ionic liquid desiccantoutlet; wherein the ionic liquid desiccant composition flows through theconditioner ionic liquid desiccant conduit; ii) a conditioner fluidconduit having: a conditioner fluid inlet; a conditioner fluid outlet;wherein a conditioner fluid flows through the conditioner fluid conduit;and iii) an impermeable exchange membrane configured between theconditioner ionic liquid desiccant conduit and the conditioner fluidconduit; wherein the conditioner fluid comprises moisture that istransferred through the conditioner impermeable exchange membrane to theionic liquid desiccant flowing through the conditioner ionic liquiddesiccant conduit; c) a regenerator; i) a regenerator ionic liquiddesiccant conduit having: an ionic liquid desiccant inlet: an ionicliquid desiccant outlet; wherein the ionic liquid desiccant compositionflows through the regenerator ionic liquid desiccant conduit; ii) aregenerator fluid conduit having: regenerator fluid inlet; a regeneratorfluid outlet: wherein the regenerator fluid flows through theregenerator fluid conduit; ii) an impermeable exchange membraneconfigured between the regenerator ionic liquid desiccant conduit andthe regenerator fluid conduit; d) a metal hydride electrochemical heattransfer device that heats the ionic liquid desiccant so that ionicliquid desiccant is heated to a temperature greater than the temperatureof ionic liquid desiccant in the conditioner; wherein the ionic liquiddesiccant flowing through the regenerator comprise moisture absorbedfrom the conditioner that is transferred through the regeneratorimpermeable exchange membrane to the regenerator fluid flowing throughthe regenerator fluid conduit; e) a pump that pumps the ionic lid iddesiccant composition in a loop from the conditioner to the regenerator:wherein the ionic liquid desiccant composition has a lower moisturecontent at the conditioner fluid outlet than at the conditioner fluidinlet and wherein the ionic liquid desiccant composition has a lowertemperature at the conditioner fluid outlet than at the conditionerfluid inlet; wherein the impermeable exchange membrane has a thicknessof no more than 25 microns comprises an ionomer and a support layer andhas a Gurley value of more than 500 seconds.
 19. The cooling system ofclaim 18, wherein the metal hydride electrochemical heat transfer devicecomprising an electrochemical pump for pumping hydrogen to an enclosurecomprising metal hydride.